Hydroxylamine derivative in the Purex Process - Part V. The single-stage reduction extraction and back extraction of neptunium with N,N-diethylhydroxylamine

N,N-diethylhydroxylamine (DEHAN) can rapidly reduce Pu(IV) and Np(VI) extractable with tri-n-butyl phosphate (TBP) to Pu(III) and Np(V) unextractable with TBP in nitric acid solution. In order to apply DEHAN in the purification cycle step of U (noted as contactor 2D) of the second cycle of the Purex Process to separate Np and Pu from U, the reduction of Np(VI) and the stability of Np(V) with DEHAN and the single-stage reduction extraction and back-extraction of Np(VI) have been studied according to the experimental conditions of contactor 2D. The results show that more than 99% of Np(VI) can entirely be reduced to Np(V) with DEHAN within a few minutes either in aqueous or in organic phase containing uranium and without containing uranium, and more than 99% of Np(VI) can be back-extracted from the organic to the aqueous phase with DEHAN as a reductant. More than 99% of Np(V) exists in nitric acid solution at least for 8 hours in presence of 0.01 mol/l DEHAN. These results are of benefit to the cascade extraction-separation of U/Np in contactor 2D in order to decontaminate Np from U.